Psychologists understand that people may not say what is on their minds either because they are unwilling or unable to do so. For example, a smoker when asked how much he or she smokes a day, may report smoking only two packs a day although the smoker actually smokes four packs a day. This may be because the smoker is embarrassed to admit the correct number of packs. This is an example of being unwilling to report a known answer. However, the smoker may report smoking only two packs a day because that is the amount the smoker honestly believes is consumed per day. This is an example of unknowingly giving an incorrect answer, also sometimes called self-deception. This example illustrates being unable to give the desired answer. The unwilling-unable distinction is like the difference between purposely hiding something from others and unconsciously hiding something from yourself. Many studies investigating psychological issues examine the thoughts and feelings that exist either outside of conscious awareness or outside of conscious control. Understanding the conscious-unconscious divergences is important to scientific psychology.